Examples of the storage system include a block storage having only the block I/O interface and a file storage having only the file I/O interface. On the other hand, in recent years, there is a demand that the block storage and the file storage be consolidated to provide both functions thereof to one device. Therefore, as disclosed in Non Patent Literature 1, there is provided a unified storage system in which one storage system includes both interfaces for the block storage and the file storage. The unified storage system includes a SAN interface and a NAS interface, and allocates storage area to the SAN interface and the NAS interface with a high degree of freedom.
Further, as disclosed in Patent Literature 2, there is known a technology which uses of virtualization technology to control a plurality of OSs to run on one piece of hardware.